I have come across an interesting and seemingly useful product for distributed caching known as NCache from alachisoft.com

The NCache is a caching solution that provides high performance and scalability, specifically targeted for .NET based Applications.
NCache Session State Module allows transparent saving and retrieval of ASP.NET session-state objects within a webfarm. It incorporates replicated caching and avoids single point of failure.

If someone has used this product before, please share the experience with others